Liver cysts are fluid-filled cavities
lined by single-layered columnar or cuboidal biliary epithelium in the liver.
Most liver cysts are found incidentally on imaging of the liver, such as
abdominal ultrasound (US), computed tomography (CT), or magnetic resonance
imaging (MRI). Hepatic cystic lesions are heterogeneous clusters; most are
simple liver cysts, but some may be malignancies, such as cystadenocarcinoma.
Simple liver cysts are thought to be congenital aberrations of biliary
development. During embryogenesis, aberrant intrahepatic bile ducts develop and
dilate to form liver cysts. Liver cysts are usually asymptomatic and do not
require special treatment. However, complications such as infections or
ruptures can cause fever or abdominal pain. In addition, large liver cysts
occasionally cause unpleasant symptoms, such as abdominal distension, jaundice,
portal hypertension, and leg edema due to compression of surrounding organs or
hepatic vasculature. The prevalence of simple liver cysts is increasingly
common with age [6].
Liver lesions are common findings in
the daily routine of radiologists. They are a complex category of pathologies
ranging from solitary benign lesions to primary liver tumors and liver
metastases. Benign focal liver lesions can arise from different types of liver
cells: epithelial (hepatocytes and bile cells) and non-epithelial (mesenchymal
cells). Diagnosis is often straightforward, although sometimes distinguishing
between primary and secondary malignancies can present a diagnostic challenge
due to the atypical appearance and characteristics of the tumor. To avoid
misdiagnosis, radiologists must address the key characteristics of the lesion
and decide which imaging procedure [for example, ultrasound, computed
tomography, and/or magnetic resonance imaging (MRI)] will most likely provide
the diagnosis. The use of advanced liver MRI techniques such as diffusion
weighted imaging (DWI), multi-arterial phase technique, hepatobiliary contrast
agents, and artificial intelligence have improved the detection and
differentiation of several focal liver lesions. Furthermore, liver MRI is often
the last imaging technique used in the diagnostic algorithm before liver biopsy
[7].

Figure 1: Trocar in situ on hepatic cyst.

Figure 2: Evacuation of sallow fluid from the
liver cyst.

Figure 3: Hepatic cyst
puncture site closure.
Simple liver cysts (SHCs) (also known
as bile duct cysts or bile cysts) are congenital parts of the ductal tree
detached from the main biliary system, which enlarge to become cystic lesions.
There is no consensus on their actual origin. Some authors believe that they
result from the dilatation of the bile duct hamartoma and do not communicate
with the biliary tract. In the literature it is reported that their prevalence
varies from 2.5 to 18%, they occur more frequently in women, with an incidence
that increases with age. SHCs are benign lesions, which are usually
asymptomatic. Cystic serous fluid is continuously produced by the cuboidal
biliary epithelium. A very large cyst can cause abdominal pain or early satiety
by squeezing. Complications, which can include bleeding or infection, are rare
and can lead to the lesion turning into a complex cyst [8].
A ciliated hepatic foregut (CHFC)
cyst is a rare cystic lesion that arises from the embryonic foregut with
approximately 100 reported cases. Most commonly identified in segment IV of the
liver, CHFC is typically asymptomatic and incidentally found on abdominal
imaging. It is important to consider this entity in the differential diagnosis
of atypical liver lesions since CHFC carries a risk of transformation into
squamous cell carcinoma. A suspicion of CHFC is therefore an indication for
surgical resection [9].
The prevalence of simple liver cysts
is 4.5-7% and they tend to be more common in women than men with a ratio of
1.5: an infected liver cyst is a condition characterized by clinical symptoms
such as fever and abdominal pain. Routes of infection include biliary,
hematogenous, nearby sites of infection, trauma, and unknown. Overall, the
routes of infection are most commonly unknown. Risk factors for infected liver
cysts are female sex, age ? 40 years, diabetes mellitus, gallstone or biliary
stricture, and pancreatic head duodenal surgery. A cyst diameter > 10 cm
increases the likelihood of exclusionary symptoms in adjacent organs. However,
there are no previous reports involving the pancreas [10].
Mucinous cysts are complex
multiseptum cysts in which mural thickening, nodularity, debris-containing fluid,
and hemorrhagic or protein-containing materials are frequently seen. Biliary
mucinous cystic neoplasm (BMCN) is one of those mucinous cysts and is a rare
benign cystic neoplasm of the biliary system, with an estimated incidence of
approximately 5% of all hepatobiliary cystic neoplasms. BMCNs can present with
a unique site that is different from their usual presentation and can
communicate with the bile duct. They occur almost exclusively (85-95%) in
middle-aged women [11].
Spontaneous rupture of a hemorrhagic
liver cyst is extremely rare. There is no standard treatment recommended for
this condition. Chogahara et al. [12], report two cases of hemorrhagic liver
cysts that ruptured spontaneously and were successfully treated with
laparoscopic deroofing. Their cases were: the first patient was an 85-year-old
man hospitalized for right hypochondralgia and sudden-onset fever. Computed
tomography revealed a 13 cm hepatic cyst occupying the right lobe of the liver
and spontaneous rupture of the cyst. Laparoscopic deroofing was performed and
continuous oozing from the cyst wall was found. In the second case, a
77-year-old woman who was being followed up for a simple liver cyst (13 cm) was
hospitalized for sudden onset right hypochondralgia. CT demonstrated a 9.9 cm
liver cyst occupying segment IV of the liver. Laparoscopic deroofing was
performed and continuous oozing from the cyst wall was observed. Histological
examination revealed a simple liver cyst. The patient was discharged on the
sixth postoperative day.
Mo et al. [13], examined patients who
received aspiration sclerotherapy with OK-432 (group A) or 99% ethanol (group
B) for symptomatic simple liver cysts and included 42 patients in group A and
39 patients in group B. No significant difference was found in the mean liver
cyst volume between the two groups. The overall success rates were 93% in group
A and 79% in group B (p = 0.08). Treatment success for cyst volumes <200ml,
200-500ml and >500ml was 100, 93 and 88% in group A and 100, 85 and 57% in
group B, respectively. The rate of symptomatic relief in group A it was higher
than in group B for cysts 500 mL (p = 0.049) and cysts <500 mL. Regarding
treatment-related complications, the incidence of injection site pain in group
A was lower than in group B. His conclusion was: single-session OK-432
sclerotherapy was safer and more effective of multiple session 99% ethanol
sclerotherapy for treatment of large cysts, although both treatments had
similar effects on small cysts.
He et al. [14], presented the
challenges of managing giant simple liver cysts causing obstructive jaundice
and compared the safety and efficacy of percutaneous aspiration and
lauromacrogol sclerotherapy with other management strategies. The case is a
39-year-old female with jaundice and liver function abnormalities. The images
revealed a giant simple liver cyst with obstruction of the intrahepatic bile
ducts. Subsequently, a combination of percutaneous catheter aspiration and
sclerotherapy with lauromacrogol was performed, obtaining satisfactory efficacy.
Therefore, a combination of percutaneous aspiration and lauromacrogol
sclerotherapy may be suggested to resolve such cases.